Apparatus for the manufacture of esters



A. A. BACKHAUS.

APPARATUS FOR THE MANUFACTUR E OF ESTERS.

APPLICATION HLED AUGJ, 191B.

Patented. Dec 2%, 1921.

at is.

THUR A. BACKHAUS, F BALTIMORE, MARYLAND, ASSIGNOR TO "U. S. INDUSTRIAL ALCOHOL 00., A CORPORATION OF WEST VIRGINIA.

APPARATUS FOR THE MANUFACTURE OF ESTERS.

To all whom it may concern:

- lowing Be it known that I, ARTHUR A. BACKHAUS, of Baltimore, in the State of Maryland, have invented a certain new and useful Improvement in Apparatus for the Manufacture of Esters, and do hereby declare that the folis a full, clear, and exact description thereof.

My invention relates to an apparatus by means of which esters may be made continuously, that is to say, Without interruption, and has reference to the manufacture of many different kinds of esters in this way.

The object of my invention is to provide an apparatus by means of which esters may be ,manufactured continuously, instead of requiring ther'epeated interruption of the operation that was hitherto found necessary. A further object is to provide an apparatus of this character by means of which esters, substantially entirely free from water, may

be obtained. Further objects of my invention will appear'from the detailed tion contained hereinafter.

While my invention is capable of being descripcarried out in many different ways, for the purpose of illustration I have shown only one type of apparatus made in accordance with my invention in the accompanying drawings, in which;

Figure 1 is a diagrammatic representation of an apparatus made in accordance with my invention, and

Fig. 2 is an enlarged vertical section of a detail of one'of the columns therein.

I shall describe my'invention as it is applied to the treatment of a weak acid, as for example, dilute acetic acid or vinegar with methyl alcohol in the production of methyl acetate,'althou'gh it is to be understood that my apparatus is applicable to the production of many diflerent esters and from materials of many different strengths.

In the drawings, I have shown a column still 1 comprised of an outer casing 2, and a large number of plates or pans3 having central openings 4 covered by hoods or bells 5, the edges of which are sealed in the liquid carried by said plates 3, the adjacent' plates being connected by overflow, pipes 6. I supply to the side of the upper part of the column still 1 continuously a quantity of sulfuric acid having a strength of 50 B. to 66 B., by means of a trapped pipe 7 leading from a sulfuric acid tank 8 having Specification of Letters Patent.

" fed, but in the alcohol from' the mama Dec. so, 19211..

Application filed August 7, 1918. Serial No. 248,755. 7

needle valve 13 and a sight feed 14. In

addition, methyl alcohol having a strength of approximately 95% is also continuously proportion of 8/10 part by weight, through a trapped pipe 15 controlled by a needle v'alve16 and a sight feed 17, leading from an alcohol tank 18. Initially,

before the mentioned feeding into the side of the-column still through the pipes 7, 11 and 15, however, sufficient methyl alcoholis fed into the apparatus to seal all the pans in the column still 1. The proportion of alcohol is varied, however, according to the strength of the acetate'that is desired to be obtained. The still 1 is heated at its lower end by means of a tubular heater 19 having. inlet and outlet steam pipes 19*. and 19 The effluent water and sulfuric acid are conducted away from the still 1 by a pipe 20 having a trap '21 therein. I From the upper portion of the still 1 a vapor discharge pipe 22 is provided to conduct away the vapors of the methyl acetate and alcohol I still 1, as well as a discharge pipe 25 for conveying the methyl acetate vapors to a, second column 26 constructed in the same manner as the column 1, except that this column is not provided with several inlets,

and with'the exception that a trapped discharge pipe 27 conveys away the methyl lower portion of said column 26 to the column l at a point which may be opposite to the entry of the pipe 15.

The vapors from the pipe 25- as cend in the column 26 through a, descending current of methyl alcohol, and the vapors of methyl acetate containing a small amount of methyl alcohol, [are conveyed by a pipe 27 -to a dephlegmator 28 from which the condensed methyl alcohol returns by a trapped pipe 29 to the top of the column 26, while the vapors of methyl acetate are conducted by a pipe 30 to a condenser 31 from which the condensed methyl acetate is drawn ofi by a pipe 32. The methyl acetate produced in this manner is substantially water-free as shown by test with anhydrous copper sulfate.

In the operation of my invention, the sul- .furic acid, the dilute organic acid, as for example, vinegar and methyl alcohol are fed larger the quantity continuously into the still 1, the reaction by which methyl acetate is formed, takes place within said column, and the heat which is applied to said column drives off the vapors of methyl acetate and methyl alcohol from the top of the column to the dephlegmator, from which the condensed water carrying some acohol is returnedto the top of the column to form liquid seals and to provide a descending body of methyl alcohol therein. The methyl acetate vapors, thus partly freed from methyl alcohol, pass them to the second or rectifying column 26 in which nearly all of the methyl alcohol is removed and returned as a liquid to the column 1, while the methyl acetate vapors containing a small amount of methyl alcohol pass out of the same into the dephlagmator 28 from which point the remaining quantity. of methyl alcohol is returned to the column 26. The methyl acetate vapors then pass to the condenser 31 from which the condensed methyl acetate is continually drawn oif.

lln carrying out the operation the esterification is carried out more completely and more rapidly by reason of the continual removal of the acetate from the place where the reaction takes place and because of the provision of much larger quantities of methyl alcohol than are needed for the reaction. The quantity of methyl alcohol present may be four or five times the quan-.

tity of methylalcohol required in the reaction. Furthermore, the smaller the percentage of the acetic acid in the descending current of liquid in the still 1, which becomes weaker in the acid as it descends, the

of methyl alcohol requiredto offset the difficulty of esterificaa large quantity of methyl alcohol is fed in at a point where the liquid is very weak in acetic acid and in such quantity as to complete the esterification before the liquid reaches the lower end of the column still 1.

It will be understood that other acids and other alcohols may be used instead of the methyl alcohol and acetic acid, such for example, as formic acid and ethyl alcohol. Also crude pyroligneous acid may be used as it contai s acetic acid and methyl alcohol etc. A so, instead of sulfuric acid another catalyst may be used, as niter cake,

or hydrochloric or any phosphoric acid.

Organic acids such as acetic acid may also be used as a catalytic, for example in the promotion ofthose reactions. into which they do not actually enter as reacting ingredients.

While I have described my invention above in detail,I wish it to be understood that many changes may be made therein without departing from the spirit thereof.

1 claim:

1. The combination of a column still, inlet pipes near the top thereof connected to separate containers, an inlet pipe near the bottom thereof connected to a container, an outlet near the bottom of' the still, a second column still, a delivery pipe leading from the top of the first still to the second still, a return pipe leading from the bottom of the second still to a point near the bottom of the first still, and a vapor exit for the second still.

2. The combination of a column still, inlet pipes near the top thereof and an inlet pipe near the bottom connected to containers respectively, an outlet near the bottom of the still, a second column still, a pipe leadin from the top of the first still to a short dlstance apart vertically, an inlet pipe to the lower part of the still, a second still,

a pipe. provided with a condenser leading from the first to the middle of the second still, a return pipe from the bottom of the second still to the first still, a vapor exit and condenser for the second still near the 'top thereof.

4. The combination of a column still, inlet pipes a short distance apart vertically leading to the top of the still, an inlet pipe leading to the bottom of the still, all of said pipes connected to containers above the still, an outlet at the bottom of the still, a second still, a pipe provided with a condenser and return pipe leading to the middle of the second still from the top of the first still, a return pipe leading from the bottom of the second still to near the bottom of the first still, a vapor exit at the top of the second still provided with a condenser and return pipe, and a condenser connected to the vapor exit of. said latter condenser.

In testimony that I claim the foregoing J. B. 'JoHNsoN. 

